The present invention relates to golf club heads and, more particularly, to the design of golf club heads.
In general, golf club heads are designed as either solid bodies (for example, persimmons), plates (for example, irons and putters with perimeter weights), or shells with a diaphragm face (for example, metal drivers and fairway woods). Today, the general consensus is that a shell with a diaphragm face provides the optimal design solution for a golf club head, with incremental improvements on that design helping to improve how far and how accurately a golfer can hit the golf ball.
For example, as discussed in U.S. Pat. No. 6,348,015, the face of a “shell” golf club head is designed from a material having a natural frequency between 2800 Hz and 4500 Hz. Upon hitting the material, the golf ball undergoes smaller deformations and, hence, lower energy losses. Or, as discussed in U.S. Pat. No. 6,348,013, a “shell” golf club head is designed with one or more recesses in one or more of the head's walls. The recesses increase the amount of time the face of the head remains in contact with the ball, again reducing energy loss.
Similarly, in U.S. Pat. No. 6,267,691, the face of a “shell” golf club is reinforced with parallel ribs along the back side of the face, controlling how the face bends under impact load. The ribs help resist bending of the face in a direction parallel to the ribs, but permit bending of the face in a direction perpendicular to the ribs. The reinforcing ribs help dampen the head's vibrations and give the face a larger region in which there is an efficient transfer of energy from the face to the ball (known as the “sweet spot”).